The charge ports on non-Teslas, meanwhile, are also in a different spot on the vehicle, meaning they may have to park parallel to a Supercharger, taking up two spots. That's what happened here; "I had no choice but to park in a way that blocks two stalls," according to the Rivian driver.
Sounds like this guy sucks too unless there were a bunch of spots open or extenuating circumstances.
Others responded that they thought this type of conflict might happen and that it's "unwise" for Tesla to open chargers to other brands while keeping the "Tesla Charging Only" signs up.